The present invention is directed generally to embodiments of a new compressed-air compressor for a compressed-air system of a vehicle and a method of operating same.
Compressed-air compressors of the general type under consideration are used, for example, for producing compressed air for pneumatic brake systems in utility vehicles—that is, heavy goods vehicles. In the field of passenger motor vehicles, compressed-air compressors are used, for example, for producing compressed air for pneumatic ride-height control systems. In the field of utility vehicles, the compressed-air compressors are generally driven by means of the drive engine of the vehicle. In the field of passenger motor vehicles, the compressed-air compressors are driven by means of an electric motor provided specifically for such purpose.
A compressed-air compressor of the general type under consideration can be designed as a piston machine and therefore has a cylinder and a piston arranged in the cylinder. The piston divides the interior space of the cylinder into a compression chamber and a chamber separated therefrom at the pressure side that is generally connected to the crankcase of the compressor. The chamber is referred to hereinafter as the “neutral chamber.”
The operation of such a piston compressor involves a suction phase, in which the volume of the compression chamber is increased as a result of a piston movement and, in the process, air is sucked in from atmosphere and conducted via an inlet valve into the compression chamber. The suction phase is followed by a compression phase, in which the volume of the compression chamber is reduced as a result of an opposite movement of the piston. Here, the inlet valve is closed, such that the air situated in the compression chamber cannot escape. The air in the compression chamber is compressed until the piston reaches its top dead center and the volume of the compression chamber is minimized, or until the compressed air has been discharged via an outlet valve to components of the compressed-air system that are connected to the compressor outlet. During the compression phase, the torque to be imparted for driving the compressor increases up to its maximum value. The maximum value falls back to zero as top dead center is reached.